Telephone-exchange apparatus.



' E. TANKEL TELEPHONE EXCHANGE APPARATUS. APPLICATION FILED JUNE 1'], 1905.

q\ Llfitehted Sept. 29, 1908.

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hi f 2M ofthe King of Prussia, German Em resident of Berlin; Germany,"have invented new and useful Improvements in TelephonevExchange Apparatus; and in order that To all whom-"it may concern? 3 Be it known that I, EMIL TANKE,

pire, and

. others skilled in: the ant '1nay imakeanduse my invention 'Igive the. following description and specification thereofix at the exchange. a a

My 'nvention relates to apparatus for tele-' phone exchanges in which each subscriber is connected withaplurality of terminal groups The object ofniy invention is to provide a telephone system of the-above character-in whlch the subscriber maiyselect' the the above character for the selective calling of twoexchange gr0ups,.-the use of one calling .my" inventiony- Fig relay common to bothgroups, connectedso that it will control. the anmlnciatorof one group when acting alone and which besides will cooperate with the selecting relay so that in energizing both relays,. thecurrent 'Will be 'swltched by means of the selecting relay or to control the annunciator of the othergroup, whereby the selective operations; of the subscriber lave .tojbe' made only'momentarily, gMy invention" further contemplates the employmentof devices ,in 'a system of the above character for "causing thesubscri berfs 35 exchange'ofiiceq; I o a In thedrawings Figure 1 is a diagrallrn matic' view representing one embodiment of are similar instrument to be supplied the central or views showing modifications.

vReferring to Fig. '1; the subscriber sstation is illustrated atf'l and .isroyi'ded with the usual microphone-m, telep one call bell in,

condenseror polarization cell 2, and receiver hook 7t.v "The subscribers station and instru-' ment T is connected by the'cjonductors land 2,: relay icoilsaand-bof a callingrrelay R and ,thencedirectly to one side of-theveentra'l battery B and to the other side ofisaid-battery" through arelay RR iflhmbattery B iszloca ted at the-centralistationiand; one pole o'undedi at-E springcontactsor j acks 51c, [0

T srHoNE- xcmaw APPARATUS.

- i Application medians 17,1905; S'eria11I oi265,7 16."

a'subject' and 7%, serve; tof connecty the .subscribersor ERLIN, GERMANY; :ASSIGNOR TO SIEMENS- & HALSKE A. orennLm, GERMANY,'AGOR1?ORATION.

f 1specificationiofilaetters Patent. 7 I PatentedSept;29,1908;

' station with other siibscribersi stations, (not showni'm theusual manner bymeansof the 'plug 'cordo 'ipand lugs S Theappairatus is illustrated in the drawing 'erative condition, the microphone and telfe'p one branch beinginterrupted, the

circuit being through the branch containing the call bell w, which is energized only by alternating current. The relay armatures are held in their 'ino era tive positions by means of springs or ct er suitable means. L L

indicateannunci'ators for showing the 1particular group "called. The selective ca ling of these groups is made by' the subscriber by means ofthe groundingkeys t 25?." If, for

? instance, thesubscriber desires to call group 1 of which the lamp L isfthe annunciator, he takes his receiver from its book h-,and )res'ses key -t .-'.-A circuit is thus made t rough which a'current 'flows from' battery 'B 'throughcoil a ofcalling relay R, conductor 1, key 1,. toground atcE back to the'battery B Coil \abeing thus energized the armature. d of'therelay R movesto make con- 'Itacts,at-c, c; A circuit is therebyestablished as follows: from the battery B through armature d, contact-c, armature a': of

.relayRz contact cilamp'L and back to the minuspole of battery B Lamp L lights up and announces the call for group l. Ar-

mature d. also closes a contact at c andtherebyshortmircuitsj coil e of relay B so that this relay, not energized current flowing through conductor If now the key't fibe released thereis made a circuit from battery through relay [coil a, f conductor 1, key t the micro hone branchof thesubscriber ssta- 'tion, con uctor 2, relay 90H 5, theshm't-cincuit around relayf'coil. e, contact'c, armature d, and back'to the battery; In. this condition relay R is energized, but no energizing of relay R? can take place on a'ccou-nt of the short circuitestablished about its coil '5.

I Relay R is so constructed andwound' that its armature d maintainsits position and. doesf'n'ot break contact at c'fc when the 1ci r ou-it' just described is made.

"The'relay consists Jof' twoexciting coils d and b which are arranged adjacent upon an iroii core with lateral arms'opposite theends of a pivotallymouhted armaturecl} the latter being :mounted upon a niddle {arm so 1 that reach. half of the corewiththefarmature' Y F i forms a-1nagnetic -circuit.- These two magnetic circuits cooperate with the common armature so that by changing the position ,of the armature there simultaneously results a 'cl'iang'e in the magnetic resistance of the circuit. By suitably arranging and proportioning the magnets and armature this change of resistance may be so adjusted that when both coils of the relay. are energized the iv- *oted armature remains in its position. his

-m.agnetic circuit or field of coil 0 overpowers that of coil 1) so that the armature d is maintained in position, closing the contacts 0, 0- In consequence of this the lamp annunciator L remains lighted notwithstanding the re lease of'key 22 until the operator at the exchange takes up the call. Also, as may be seen, the subscriber has the ability to retake or take back, his call for which purpose he has only to hang up his receiver on the hook 7t. Thisca'uses the windings a and b to be decnergized so that the armature d moves away from. the contacts 0, '0 under the influence of its spring weight, or other retractive means, and thereby the system isreturncd to inoperative condition. I

lor calling group 2 in the exchange the subscriber takes oil" the receiver from its hook and presses key t. This grounds both conductors l and 2 at E through the resistance 1". Two circuits are thereby established one of which is as follows: from the plus pole of battery B to ground E, E resistance r, station T, key t microphone branch of the subscribers station, key 25 conductor 1, coil a; of relay R back to the battery. The other circuit is as follows from the plus pole of the battery coil e ofrelay R coil 6 of relay It, conductor 2, key 13 and also through the microphone branch of the subscribcns instrument, key t, conductor 1, coil a of relay R back-to the minus pole of the battery, thus both coils of relay It are excited.

By suitably proportioning r as well as all Y the other resistances in the circuit the current through conductor 2 causes only a weak energizing of coil 1), which 1s not 'suliicici'it to prevent the attraction of the armature by the stronger magnetization due to coil 0. The armature I], therefore, closes the contact a connected with the lamp circuit, as in the :asc of a call in the first group. ltclay R is energizcd iby the current flowingthroughcontacts to contact 0.

In consequence of this and when coil 1) of relay R in consequenceof which the armature a: of relay It" is attracted away from This makes acircuit from the plus pole of the battery through armature (1, contact 0, armature w of relay 1. contact 0 annunciator L back to the bat- "tery. Lamp L -be'comes lighted; and announces the-call of group 2. As both relays R and R areenergized and means are provided that the armature tongue g is interrupting the contact at 0 before the armature 61 makes contact with c rela r R is not short cirduited as is the case in calling up the first group.

On releasing key t after the call has been made botharmatures d and w remain held in their respective positions closing the contacts' at c, c and c, the circuit being the same as that described for calling grou 1 under similar conditions; that is, throug the subscribers station and both conductor branches in seriesthe. call of group 2 is therefore maintained. On the other hand, the subscriber has again the ability to retake his call by hangin up{ his receiver, since thereby coil a of re ay 1 is left without current and the armature is-retracted away from the contacts by means of its retractive devices.

.In a similar manner to that here described for the calling of group 2 the calling of group 1 may be effected by the grounding at the same time of both conductors 1 and 2. For example, in such a way that by means of key t a direct grounding of the circuit is eliectcd without interruption of. the branch circuit formed by taking the receiver from its hook sec, for example, the modification illustrated in Fig. 2; In this case a branch circuit is formed similar to that above described for' calling the second group, but 'With the differonce that the relay coils b and e together with the subscribers station are practically shortcircuitcd through the ground circuit, so that only coil (1 is energized or effective and the calling of the. first group is obtained as above described. From this it is also apparent that the grounding point of the conductor at the subscribens station may generally be selected at will. In consequence of this the arrangement may also be such that instead of a temporary grounding by means of the key in regard to other purposes a permanent grounding may be provided in such a way that the subscriber s iall always have the possibility of retaking his call by hanging in his receivcr, as illustrated in the nio ification shown in Fig. 3.

The return of the armatures d and m to inoperative position after the call has been taken may be effected at the central station in a similar manner, as above explained for the subscribers station. A device, however, 'is shown in the drawings for pose which serves at the same time to secure automatically the inoperative position of the this purinsertion of the plug 3, 2 the grounded hat- 5 tery l3? connected with the plug cord is switched on to the Win ding b of the relay R so that by means of the current circulating through coils' e and b and ground connection a sufiiciently strong energizing of the coil 1) is effected so that armature d is inoperative osition shown, a of coil a. at c of the circuit of the lamp annunciators L L and the previouslylighted lamp will be again without current.- Relay R notwithstanding remains energized but the position of its armature is immaterial as regards the switching out of the annunciators L, In,

since the operation is determined'by armature dand contact 0 Having thus descrlbed' my invention What I claim as new and desire to secure by Letters Patent is z- 1. In a tele hone system, the combination with aplura'hty of' calling groups and their respective annunciators; station, a relay having-two coils, and a single coil relay, a-circuit leading from said subscribers station returned to the ainst the effect another clrcuit leading throu h the other coil of'said two coiled relay, an through the 1 single coiled r'elay to control another annunciator.

'2. In a tele with a plurality ofcalling groups and their respective annunciatorsj of 'a coiled relay connected in series with one coil 40 of the other relay, a circuit leading from said subscribers station through the other coil of said two coiled relay to control ,one'annunciator, and another circuit leading through the-single coiled relay and that coil .ofthe two coiled relay which is in series with it, to controlanother annunciator. I

3. In a telephone system, the combination ofa plurality of calling groups and their annunc1ators, of a subscribers station, a two coiled relay, a single coiled relay, means'for operating one annunciator from the subscribers station through one coil of said .two

coiled relay,- and means for operating another'annunciator from the subscribers staconnection by the is results from t e interruption.

through one coil of said two; 30 coiled'rela-y to control one annunciator', and

phone system, the combination subscribers station, a relay havlng'two coils, and a single of a subscribers.

' with a plurality tion through said single coiled relay and energizing both coils of said two coiled relay.

4. In a telephonesystem, the combination of calling groups and their respective annunciators'; of a subscribers station, a two coiled relay, a single coiled relay in series with one coil of the two coiled relay, means for operating one 'annun'ciator from the subscriber s station through one coil of thetwo coiled relay, and short circuiting the single coiled relay, and means for operating another annunciator from the subscribers station through said single coiled relay and energizing both coils of said two coiled relay. a

5. In a telephone system, the combination of a central station having a plurality of calling groups and their respective annunciators,

a subs'cribers station, a two-branched con:

ductor connecting the stations, keys at the subscribers" stations for selectively calling corres onding groups at the central station, a relay or controlling the group circuits having a pivoted armature, coils on the relay one in each branch of the'conductor, with the armature of the relay forming a sep arate magnetic circuit whereby when both coils of the relay are energized the previous position of the armature is not changed. 7

1 6. In-a telephone system, the combination of a central station having a plurality of calling groups,

onding severally to said groups, necting the station with subscribers stations, a relay controlling the annunciator circuits of the calling grou s, said relay having two coils one .in each 0 said conductor branches,

each coil selective means at the S11b scribers station corres two-branc ed conductors consaid coils each forming a separate magnetic circuit in the relay,whereby when both coils of the relay are energized, the previous position of the armatureis not changed a second relay having its coil in series with one of the coils on the first relay, said second relay selectively controlling the annunciator circuit in accordance with the operated-subscribers key,

and meanscompri'sing the usual plug cord switching connections'at the central station for disconnecting the annunciator circuits from the; subscriber's station. i

' EMIL TANKE.

Witnesses: r

' WoLnEMARHAUP'r,

H NRY HAsPEnl 

